Im under the same debate tbh. I WAS going for a 182 but the way tax is looking im not going to bother. The 1.2 just doesnt cut it anymore, power, gear ratios etc, always finding i need thta bit mroe power to get myself out of trouble. So i figured id go for the 1.6 16v clio, itl be my third clio. Hoping to snatch up a 20k miler on a 05 or 55 plate. They arent exactly shy either, ive seen about 2 come out on meets and they do put up a decent fight - no matter what people say, but hands down the 172 will beat it.
I wouldnt go for the diesel simply due to the lack of revs and also because itl most likely be an 8v. Driven a few 8v cars and cant say i like the engine character, theyre noisy in most cases and also diesel is a joke right now..
Go for the clio. Cheap to insure if your the right age, ill be 20, cheap to run and okay to tax. If you can, get it decked on a decent set of springs or some coilovers.